Angular TextInput Components don't seem to function properly when dealing with arrays

I am trying to create a collection of text input components with values stored in an array. However, when using the following code, the values seem to be placed incorrectly in the array and I cannot identify the bug.

<table>
  <tr *ngFor="let option of this.options; let i = index">
    <td style="width:100%">
      <textinput2 (textchange)="this.options[i] = $event;" class="lessmargin" type="text" [value]="this.options[i]">
      </textinput2>
    </td>
    <td valign="top">
      <button [attr.disabled]="this.options.length >= 3 ? null : ''" (click)="this.options.splice(i, 1)" style="top:0;" class="btn btn-outline-danger">-</button>
    </td>
  </tr>
</table>

<a (click)="this.options.push('')" class="showmore">+ Add another option</a>

Textinput2 Component:

<div class="form-group">
  <label *ngIf="this.placeholder && this.labelsize == 'big'" for={{randomid}}><h5>{{this.placeholder}}</h5></label>
  <label *ngIf="this.placeholder && this.labelsize == 'small'" for={{randomid}}>{{this.placeholder}}</label>
  <input [(ngModel)]="this.value" (change)="this.textchange.emit(this.value)" type={{type}} id={{randomid}} class="form-control" placeholder={{this.placeholder}}>
</div>

Thank you.

Answer №1

I'm a bit confused about what's going on, but it might be helpful to implement the trackBy function in your *ngFor loop.

As stated in the documentation:

The trackBy function determines how changes are tracked for items in the iterable.

When items are added, moved, or removed in the iterable, the directive must only re-render the necessary DOM nodes to reduce unnecessary re-renders.

By default, the change detector assumes that the object instance is used to identify nodes in the iterable. When a trackBy function is provided, the result of calling the function is used to identify the item node instead of just the object identity.

This function takes two inputs: the iteration index and the node object ID.

If you're interested in learning more about using trackBy, you can find additional information here

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